what is the difference between ADSL router(Broadband router) and normal router ?
can i use the ADSL router for connect more than one computer in a network with full access as like a normal router?

An ADSL router is to be used with ADSL connections only through your local phone company. it is usually a modem/router combination unit...meaning that the ADSL modem is part of the wireless router. You can connect/network with this type of router just as with any other broadband/cable router....only that you may find that it has limited connections set up by the phone company....They may only allow 5 computers to connect to the router or maybe 10. For sure the wireless range is lowered to only allow connections from close proximity while regular routers will broadcast about 300 feet or so.
This is regulated by the phone company and if you want more range ...you will have to pay for it.

I tell my customers that have to rely on an ADSL connection to request a modem only and not a combination ADSL modem/router combination....Once the ADSL is set up then I have them install a regular either wired or wireless router to the ADSL modem....This allows for better connectivity and less control over your network by the phone company.

can i use this ADSL router for interconnection of computer?
i tried with 2 computer but both can hav only internet connection and
cannot hav interconnection between two
is there any posiblity with this ADSL router

If you are talking about open networking...then yes you should be able to set up a home based network the same as with any router. The difference is that you might have to actually contact the ISP and have their techs configure it for you. I have seen some that required their tech support and I have seen some that didn't. The basis is that the router itself may not be accessable by the end-user.

Sharing is not based on networking but controlled by profiles in each computer on the network...So make sure that your computers have sharing capabilities.
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I have seen some ADSL that do not use a router but a joint user profile which is set up strictly by the ISP(phone company) in which the second computer must also be connected through the telephone lines as a wired connection. Is this what you have? If so then I am sure that networking and sharing files are not allowed in this context. Only the sharing of the internet connection!